But since \( f(f(x)) \) is odd (as composition of odd functions), and \( x \) is odd, the equation \( f(f(x)) = x \) is equivalent to \( g(x) = 0 \) where \( g \) is a degree â‰¤ 9 polynomial, odd.

Tue, 21 Apr 2026 15:39:43 +0000

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